Reliability DEM

Yeah, laser scans are cool but the gear to do it costs 50X... 

Cover an area that is larger than what you need. The edges get less overlap and thus have lower accuracy. 

User Terrain Awareness in your data collection. 

Relative measurements should be pretty solid but will certainly have a cumulative error as the distance of the measurement area increases.

Use GCPs to apply linear corrections to the elevation. 

120 meters is really high if you want to be getting good detail. 

80% overlap should be good but your most recent map is showing overlap of roughly 60% overlap. 

Hi, thanks for your answer. As an example, for this project I would need to have an correct DEM: 
https://www.mapsmadeeasy.com/maps/public/4c190950f0a944688ee9157582902e82

the most important part is in the middle of the area, so the edges shouldn't be the problem. 

Whats a GCP and how can is use it?

Which settings do you recommend to get the best result?

Tanks for your help!

https://support.dronesmadeeasy.com/hc/en-us/articles/360000518146-Manual-Rereferencing

60m at 80% overlap with Terrain Awareness usually turns out great.

The absolute accuracy is increased if you include the Ground Reference Image with your uploaded dataset. 

Still have problems with DEM. To make sure its not a problem with my hardware (mavic 2 pro), i compared the creation of a DEM with the software Pix4D. The result was, i have huge differences between both DEMs (Up to 40 m). The DEM of MME got height differences, which can not be realistic. The DEM of Pix4D seems to be correct. Dont know if i have the wrong settings…

As noted in the Data Collection guidelines you should be using at least 75% overlap, not the 70% you are setting the app to. You can see the gaps in your coverage in the Overlap Report. If you care about the elevation accuracy of the results you need to have the Overlap Report be fully dark blue (use 80%).

Also, you appear to be using Connectionless data collection mode (triggered on the aircraft). This will not give you the best possible results. Active Connect mode should be used if possible. 

https://support.dronesmadeeasy.com/hc/en-us/articles/217006946-Connectionless-Mapping

It looks like you have used a ground reference image so it is possible that the result from MME is more accurate than one created using other software. 

Zane,My DEMs are way off.  I am mapping saltmarsh, which is essentially flat with a potential contour interval of 8 feet.  I am getting contour intervals of 22 meters.  The center is high and the edges fall off.  I flew at 300 feet with 80% overlap, without terrain awareness.  Is it my drone?  A Mavic Pro.  The image attached is from the contour (1 m) plugin for QGis.

The curvature is caused by slight disagreements in the feature matching. The Mavic Pro camera isn't great but 80/80 is pretty good overlap. The time of day might have something to do with it. The sun is rising quickly at that time which means the shadows are moving a lot from the time you start the data collection to the time it is finished. 

The Mavic 3 Enterprise creates the nicest and flattest maps out of any camera we see regularly. 

Correcting the distortion is beyond what we can provide in support but there are plugins in QGIS that can help dewarp the DEM.